Figure 7. PDE4 inhibitors reduce H1N1 influenza-induced lung injury.

C57/BL6 mice were challenged with H1N1 (10⁵ pfu/mouse, i.t.) for up to 6 days. For compound treatment, a stock solution (5 mg/ml) was added to the drinking water (containing 2% sucrose) to a final concentration of 30 µg/ml. A. Survival studies of mice administered i.t. with H1N1 (10⁵ pfu/mouse, n = 6 mice/group). Mice were then euthanized using pentobarbital and lungs were lavaged with saline, harvested, and then homogenized. Cell counts and lavage protein were measured (B, C). Lavage cytokine secretions were measured (D, E). Serum samples were also collected and cytokine levels were measured (F, G). H. H&E staining was performed on lung samples. Original magnification, ×60. The data represent n = 4–6 mice/group, *P<0.05 versus vehicle.